In vivo expression technology. A promoter-trapping technique that selects microbial promoters that are active in a specified niche, e.g. during the interaction of a microorganism with its host. Bacterial DNA is cloned randomly into a plasmid carrying a promoter trap which consists of a promoterless essential growth factor or antibiotic resistance gene and a linked reporter gene. This plasmid is then used to infect a host strain that is deficient in the growth factor or resistance gene and survival indicates that the promoter is specifically active under the conditions being experienced by the host. Constitutive promoters can be excluded by looking at expression of the reporter gene. The original technique has been modified in various ways and is a powerful approach for functional genomics.
Subjects: Medicine and Health.